CYP2C19 Inhibition: The Impact of Substrate Probe Selection on in Vitro Inhibition Profiles

Foti, R.; Wahlstrom, Jan L.

doi:10.1124/dmd.107.019265

Cited by 61 publications

(41 citation statements)

References 28 publications

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“…The selection of appropriate CYP3A4 probe substrates for in vitro studies has led to substantial debate. CYP2C9 (Kumar et al, 2006), CYP2C19 (Foti and Wahlstrom, 2008), and CYP3A4 (Kenworthy et al, 1999; Stresser et al, 2000) have exhibited probe substrate-dependent inhibition for in vitro studies. The correlation analysis of CYP3A4 DDI data from in vitro experiments has suggested that at least three probe substrate classes may exist for CYP3A4: benzodiazepine-like, dihydropyridine-like, and testosterone-like, possibly due to the presence of multiple binding regions within the CYP3A4 active site (Kenworthy et al, 1999).…”

Section: Discussionmentioning

confidence: 99%

Selection of Alternative CYP3A4 Probe Substrates for Clinical Drug Interaction Studies Using In Vitro Data and In Vivo Simulation

Foti¹,

Rock²,

Wienkers³

et al. 2010

Drug Metab Dispos

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116

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ABSTRACT:Understanding the potential for cytochrome P450-mediated drugdrug interactions (DDIs) is a critical step in the drug discovery process. DDIs of CYP3A4 are of particular importance because of the number of marketed drugs that are cleared by this enzyme. In response to studies that suggested the presence of several binding regions within the CYP3A4 active site, multiple probe substrates are often used for in vitro CYP3A4 DDI studies, including midazolam (the clinical standard), felodipine/nifedipine, and testosterone. However, the design of clinical CYP3A4 DDI studies may be confounded for cases such as 1-(2-hydroxy-2-methylpropyl)-N-[5-(7-methoxyquinolin-4-yloxy)pyridin-2-yl]-5-methyl-3-oxo-2-phenyl-2,3-dihydro-1H-pyrazole-4-carboxamide (AMG 458), with which testosterone is predicted to exhibit a clinically relevant DDI whereas midazolam and felodipine/nifedipine are not. To develop an appropriate path forward for such clinical DDI studies, the inhibition potency of 20 known inhibitors of CYP3A4 were measured in vitro using 8 clinically relevant CYP3A4 probe substrates and testosterone. Hierarchical clustering suggested four probe substrate clusters: testosterone; felodipine; midazolam, buspirone, quinidine, and sildenafil; and simvastatin, budesonide, and fluticasone. The in vivo sensitivities of six clinically relevant CYP3A4 probe substrates (buspirone, cyclosporine, nifedipine, quinidine, sildenafil, and simvastatin) were determined in relation to midazolam from literature DDI data. Buspirone, sildenafil, and simvastatin exhibited similar or greater sensitivity than midazolam to CYP3A4 inhibition in vivo. Finally, Simcyp was used to predict the in vivo magnitude of CYP3A4 DDIs caused by AMG 458 using midazolam, sildenafil, simvastatin, and testosterone as probe substrates.The cytochrome P450 (P450) superfamily of drug-metabolizing enzymes is involved in the metabolism of the majority of currently prescribed drugs and new chemical entities. Within the P450 superfamily, CYP3A4 is responsible for the metabolism of approximately 55% of marketed drugs (Wienkers and Heath, 2005). Because of its general importance in drug clearance, assessment and modeling of CYP3A4 inhibition are a critical part of the drug discovery and development process. Probe substrate-dependent inhibition profiles have been observed in vitro with CYP3A4, possibly owing to the presence of multiple probe substrate binding regions within the CYP3A4 active site (Kenworthy et al., 1999). In response, a standard approach when testing for CYP3A4 inhibition has been to use multiple probe substrates such as midazolam (the clinical standard), felodipine/nifedipine, or testosterone for in vitro experiments (Wienkers and Heath, 2005). Extrapolation of the in vitro data to the in vivo situation may be confounded in the multiple probe substrate scenario if a probe substrate that is not clinically relevant, such as testosterone, is markedly more susceptible to inhibition than midazolam (the clinical standard) and felodipine/nifedipine . Our first a...

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Section: Discussionmentioning

confidence: 99%

Selection of Alternative CYP3A4 Probe Substrates for Clinical Drug Interaction Studies Using In Vitro Data and In Vivo Simulation

Foti¹,

Rock²,

Wienkers³

et al. 2010

Drug Metab Dispos

Self Cite

116

View full text Add to dashboard Cite

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“…Accepted major +ve Perpetrators of CYP-mediated pharmacokinetic drug-drug interactions sensitivities of in vivo probes for drug metabolizing CYP enzymes other than CYP3A still require formal evaluation, particularly for CYP2C9 and CYP2C19, which together with CYP3A exhibit substrate-dependent inhibition in vitro [24,25]. The use of objective criteria facilitates appropriate re-classification when new information emerges.…”

Section: Cyp Inhibitorsmentioning

confidence: 99%

Perpetrators of pharmacokinetic drug–drug interactions arising from altered cytochrome P450 activity: a criteria‐based assessment

Polasek

Lin

Miners

et al. 2011

Brit J Clinical Pharma

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WHAT IS ALREADY KNOWN ABOUT THIS SUBJECT• Many drugs inhibit or induce cytochrome P450 enzymes (CYP) to cause clinically significant changes in the concentrations of other drugs, i.e.'perpetrate' pharmacokinetic drug-drug interactions (PK-DDIs).• Tables that list the substrates, inhibitors and inducers of CYP are common, but they lack consistency and are constructed from evidence of variable quality. WHAT THIS STUDY ADDS• This is the first study to catalogue important perpetrators of PK-DDIs using objective criteria and clinical pharmacokinetic drug interaction studies. This information is intended to inform clinical decisions on PK-DDIs.• Existing tables of CYP inhibitors and inducers have low sensitivity and low positive predictive value in identifying the major perpetrators of PK-DDIs. • Several drugs were identified which potentially perpetrate CYP-mediated PK-DDIs, but quality clinical pharmacokinetic interaction studies are lacking. This information may be used to inform future research. AIMSTo catalogue the perpetrators of CYP-mediated pharmacokinetic drug-drug interactions (PK-DDIs) using clinically relevant criteria, and to compare this with an analogous catalogue. METHODSCandidate inhibitors and inducers of CYP1A2, CYP2C9, CYP2C19, CYP2D6 and CYP3A ('perpetrators') were evaluated using published clinical pharmacokinetic interaction studies. Studies were selected on the basis of Նsix human subjects, use of a validated in vivo probe substrate for the CYP enzyme, and clinically relevant dosing. Inhibitors were described according to the FDA classifications of strong, moderate or weak, whereas inducers were classified as major (Նtwofold decrease in AUC) or weak (

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“…Fluoxetine also undergoes CYP2C19-mediated O-dealkylation to the p-trifluoromethylphenol metabolite (Liu et al, 2002). In addition, racemic fluoxetine and/or its enantiomers have been shown to be reversible inhibitors of CYP2D6 (Brosen and Skjelbo, 1991;Stevens and Wrighton, 1993), CYP2C19 (Kobayashi et al, 1995;Foti and Wahlstrom, 2008), CYP3A4 (von Moltke et al, 1994;Ring et al, 1995), and CYP2C9 (Schmider et al, 1997;Hemeryck et al, 1999). Fewer studies have been conducted examining the potential for fluoxetine to be a mechanism-based inhibitor of P450.…”

mentioning

confidence: 99%

Differential Time- and NADPH-Dependent Inhibition of CYP2C19 by Enantiomers of Fluoxetine

Stresser

Mason²,

Perloff³

et al. 2009

Drug Metab Dispos

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] is a widely used selective serotonin reuptake inhibitor, with more than 23 million prescriptions filled for the generic drug within the United States in 2006 (http://www.drugtopics.com/Topϩ200ϩ Drugs). Racemic fluoxetine and its (R)-and (S)-enantiomers are metabolized by N-demethylation to the pharmacologically active metabolite norfluoxetine by CYP2D6 and other cytochrome P450 (P450) isoforms (Margolis et al., 2000;Mandrioli et al., 2006; refer to latter for chemical structure). Fluoxetine also undergoes CYP2C19-mediated O-dealkylation to the p-trifluoromethylphenol metabolite (Liu et al., 2002). In addition, racemic fluoxetine and/or its enantiomers have been shown to be reversible inhibitors of CYP2D6 (Brosen and Skjelbo, 1991;Stevens and Wrighton, 1993), CYP2C19 (Kobayashi et al., 1995;Foti and Wahlstrom, 2008), CYP3A4 (von Moltke et al., 1994;Ring et al., 1995), and CYP2C9 (Schmider et al., 1997;Hemeryck et al., 1999). Fewer studies have been conducted examining the potential for fluoxetine to be a mechanism-based inhibitor of P450. Mayhew et al. (2000) showed fluoxetine to be a mechanism-based inhibitor of CYP3A4, and McGinnity et al. (2006) recently demonstrated time-and concentration-dependent inhibition of CYP3A4 and also CYP2C19 in multiple in vitro systems, including hepatocytes. With heightened awareness of links between mechanism-based inhibitors, covalent binding and idiosyncratic toxicity (Ulrich, 2007), as well as the appearance of regulatory guidance for drugdrug interaction testing (U.S. Food and Drug Administration, http:// www.fda.gov/cber/gdlns/interactstud.htm.), many laboratories are establishing or revisiting their procedures for conducting time-dependent P450 inhibition testing. In the process of augmenting our laboratory's CYP2C19 time-dependent inhibition assay, we tested model compounds intended to serve as reference inhibitors. In many laboratories, ticlopidine is used as a positive control inhibitor in this assay (Ha-Duong et al., 2001), but we and others have found it to be only weakly inhibitory (Stresser et al., 2008), and it is therefore unsatisfactory as a potent acting benchmark. In this report, we confirm the findings of McGinnity et al. (2006) with racemic fluoxetine and show that the enantiomers of fluoxetine are effective, but kinetically different, time-dependent inhibitors of CYP2C19. Materials and MethodsMaterials. Pooled human liver microsomes (HLM), S-benzylnirvanol, (S)-mephenytoin, (Ϯ)4Ј-OH-mephenytoin, and stable-isotope-labeled (Ϯ)4Ј-hydroxy mephenytoin-D3, were obtained from BD Biosciences (Woburn, MA). All other chemicals, including (Ϯ)-fluoxetine, (R)-fluoxetine, (S)-fluoxetine, (Ϯ)-norfluoxetine, and ticlopidine were obtained from Sigma-Aldrich (St. Louis, MO).S-Mephenytoin 4-Hydroxylase IC 50 Shift Assays. Inhibition by test chemicals was determined using seven concentrations of inhibitor, separated by 0.5 log spacing, in a final volume 0.4 ml. Reactions contained 40 M S-mephenytoin (approximately the K M ), 0.3 mg/ml of pooled HLM, 1.3 mM NADPϩ, 3.3 mM gl...

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CYP2C19 Inhibition: The Impact of Substrate Probe Selection on in Vitro Inhibition Profiles

Cited by 61 publications

References 28 publications

Selection of Alternative CYP3A4 Probe Substrates for Clinical Drug Interaction Studies Using In Vitro Data and In Vivo Simulation

Selection of Alternative CYP3A4 Probe Substrates for Clinical Drug Interaction Studies Using In Vitro Data and In Vivo Simulation

Perpetrators of pharmacokinetic drug–drug interactions arising from altered cytochrome P450 activity: a criteria‐based assessment

Differential Time- and NADPH-Dependent Inhibition of CYP2C19 by Enantiomers of Fluoxetine

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